$3

`c
#include "stdlib/napi/argv_int64.h"
`

#### stdlib_napi_argv_int64( env, value, \out, \message, \*err )

Converts a Node-API value to a signed 64-bit integer.

`c
#include "stdlib/napi/argv_int64.h"
#include
#include

static napi_value addon( napi_env env, napi_callback_info info ) {
napi_value value;

// ...

int64_t out;
napi_value err;
napi_status status = stdlib_napi_argv_int64( env, value, &out, "Must be a number.", &err );
assert( status == napi_ok );
if ( err != NULL ) {
assert( napi_throw( env, err ) == napi_ok );
return NULL;
}

// ...
}
`

The function accepts the following arguments:

- env: [in] napi_env environment under which the function is invoked.
- value: [in] napi_value Node-API value.
- out: [out] int64_t* destination for storing output value.
- message: [in] char* error message.
- err: [out] napi_value* pointer for storing a JavaScript error. If not provided a number, the function sets err with a JavaScript error; otherwise, err is set to NULL.

`c
napi_status stdlib_napi_argv_int64( const napi_env env, const napi_value value, int64_t out, const char message, napi_value *err );
`

The function returns a napi_status status code indicating success or failure (returns napi_ok if success).

#### STDLIB_NAPI_ARGV_INT64( env, name, argv, index )

Macro for converting an add-on callback argument to a signed 64-bit integer.

`c
#include "stdlib/napi/argv_int64.h"
#include "stdlib/napi/argv.h"
#include
#include

static int64_t fcn( const int64_t v ) {
return v;
}

// ...

static napi_value addon( napi_env env, napi_callback_info info ) {
// Retrieve add-on callback arguments:
STDLIB_NAPI_ARGV( env, info, argv, argc, 1 );

// Convert the first argument to a C type:
STDLIB_NAPI_ARGV_INT64( env, value, argv, 0 );

// ...

int64_t out = fcn( value );
}
`

The macro expects the following arguments:

- env: environment under which the callback is invoked.
- name: output variable name.
- argv: name of the variable containing add-on callback arguments.
- index: argument index.